Hydraulic vehicle brake systems with an anti-skid and traction control apparatus have a pressure control valve assembly in a brake line that extends between a master brake cylinder and at least one wheel brake. This pressure control valve assembly serves to modulate brake pressure in the wheel brake if the danger of wheel locking or a loss of traction at the associated vehicle wheel occurs. In the case of a loss of traction, a high-pressure pump of the brake system pumps pressure fluid into the brake line. So that the pressure fluid does not drain out through the master brake cylinder, a shutoff valve in the form of an electromagnetically-actuated 2/2-way valve is disposed in the brake line between the feed point of the pump and the master brake cylinder. Since the pump, when pressure fluid is not withdrawn, would cause an impermissibly great brake connected parallel to the shutoff valve.
A 2/2-way valve of the type referred to at the outset is known for instance from U.S. Pat. No. 4,529,166. Under the influence of the restoring spring, this valve assumes its open position, in which both valve connections communicate hydraulically. The generation of a magnetic field moves the armature counter to the action of the restoring spring, so that it presses the closing body against the valve seat: the valve is now in its closing position. The closing body, received longitudinally displaceably in the armature, is then under the influence of a compensation spring supported firmly on the housing. There is no particular provision made for limiting impermissibly high pressures occurring on the downstream side.